1. Field of the Invention
This invention relates to an audio device and particularly to a tone control cancelling circuit in which tone control is forcedly cancelled on operating an equalizer unit.
2. Description of Prior Art
In a conventional radio, stereo and the like for use in a car having an electronic control circuit for adjusting volume and tone (balance, bass and treble), the control circuit has been operative even upon operating an equalizer unit. Therefore, the control circuit has been liable to be mis-operated coincidentally with the operation of the equalizer unit. If it is once mis-operated, the bass and treble characteristics values, particularly, of the tone characteristic value turn out to deviate from predetermined level values, whereby there occurs necessity of resetting level values.
At the same time, such deviation causes the tone characteristic value to exceed the designed allowance of the device to thereby produce vibration and wave form distortion which may make a user uncomfortable.